package com.baomidou.kisso.common.bcprov.asn1;

import java.io.IOException;
import java.util.Enumeration;
import java.util.Vector;

public abstract class ASN1Sequence extends ASN1Primitive {

	protected Vector seq = new Vector();


	/**
	 * return an ASN1Sequence from the given object.
	 *
	 * @param obj the object we want converted.
	 * @exception IllegalArgumentException if the object cannot be converted.
	 */
	public static ASN1Sequence getInstance( Object obj ) {
		if ( obj == null || obj instanceof ASN1Sequence ) {
			return (ASN1Sequence) obj;
		} else if ( obj instanceof ASN1SequenceParser ) {
			return ASN1Sequence.getInstance(((ASN1SequenceParser) obj).toASN1Primitive());
		} else if ( obj instanceof byte[] ) {
			try {
				return ASN1Sequence.getInstance(fromByteArray((byte[]) obj));
			} catch ( IOException e ) {
				throw new IllegalArgumentException("failed to construct sequence from byte[]: " + e.getMessage());
			}
		} else if ( obj instanceof ASN1Encodable ) {
			ASN1Primitive primitive = ((ASN1Encodable) obj).toASN1Primitive();

			if ( primitive instanceof ASN1Sequence ) {
				return (ASN1Sequence) primitive;
			}
		}

		throw new IllegalArgumentException("unknown object in getInstance: " + obj.getClass().getName());
	}


	/**
	 * Return an ASN1 sequence from a tagged object. There is a special
	 * case here, if an object appears to have been explicitly tagged on 
	 * reading but we were expecting it to be implicitly tagged in the 
	 * normal course of events it indicates that we lost the surrounding
	 * sequence - so we need to add it back (this will happen if the tagged
	 * object is a sequence that contains other sequences). If you are
	 * dealing with implicitly tagged sequences you really <b>should</b>
	 * be using this method.
	 *
	 * @param obj the tagged object.
	 * @param explicit true if the object is meant to be explicitly tagged,
	 *          false otherwise.
	 * @exception IllegalArgumentException if the tagged object cannot
	 *          be converted.
	 */
	public static ASN1Sequence getInstance( ASN1TaggedObject obj, boolean explicit ) {
		if ( explicit ) {
			if ( !obj.isExplicit() ) {
				throw new IllegalArgumentException("object implicit - explicit expected.");
			}

			return ASN1Sequence.getInstance(obj.getObject().toASN1Primitive());
		} else {
			//
			// constructed object which appears to be explicitly tagged
			// when it should be implicit means we have to add the
			// surrounding sequence.
			//
			if ( obj.isExplicit() ) {
				if ( obj instanceof BERTaggedObject ) {
					return new BERSequence(obj.getObject());
				} else {
					return new DLSequence(obj.getObject());
				}
			} else {
				if ( obj.getObject() instanceof ASN1Sequence ) {
					return (ASN1Sequence) obj.getObject();
				}
			}
		}

		throw new IllegalArgumentException("unknown object in getInstance: " + obj.getClass().getName());
	}


	/**
	 * create an empty sequence
	 */
	protected ASN1Sequence() {
	}


	/**
	 * create a sequence containing one object
	 */
	protected ASN1Sequence( ASN1Encodable obj ) {
		seq.addElement(obj);
	}


	/**
	 * create a sequence containing a vector of objects.
	 */
	protected ASN1Sequence( ASN1EncodableVector v ) {
		for ( int i = 0 ; i != v.size() ; i++ ) {
			seq.addElement(v.get(i));
		}
	}


	/**
	 * create a sequence containing a vector of objects.
	 */
	protected ASN1Sequence( ASN1Encodable[] array ) {
		for ( int i = 0 ; i != array.length ; i++ ) {
			seq.addElement(array[i]);
		}
	}


	public ASN1Encodable[] toArray() {
		ASN1Encodable[] values = new ASN1Encodable[this.size()];

		for ( int i = 0 ; i != this.size() ; i++ ) {
			values[i] = this.getObjectAt(i);
		}

		return values;
	}


	public Enumeration getObjects() {
		return seq.elements();
	}


	public ASN1SequenceParser parser() {
		final ASN1Sequence outer = this;

		return new ASN1SequenceParser() {

			private final int max = size();

			private int index;


			public ASN1Encodable readObject() throws IOException {
				if ( index == max ) {
					return null;
				}

				ASN1Encodable obj = getObjectAt(index++);
				if ( obj instanceof ASN1Sequence ) {
					return ((ASN1Sequence) obj).parser();
				}
				if ( obj instanceof ASN1Set ) {
					return ((ASN1Set) obj).parser();
				}

				return obj;
			}


			public ASN1Primitive getLoadedObject() {
				return outer;
			}


			public ASN1Primitive toASN1Primitive() {
				return outer;
			}
		};
	}


	/**
	 * return the object at the sequence position indicated by index.
	 *
	 * @param index the sequence number (starting at zero) of the object
	 * @return the object at the sequence position indicated by index.
	 */
	public ASN1Encodable getObjectAt( int index ) {
		return (ASN1Encodable) seq.elementAt(index);
	}


	/**
	 * return the number of objects in this sequence.
	 *
	 * @return the number of objects in this sequence.
	 */
	public int size() {
		return seq.size();
	}


	public int hashCode() {
		Enumeration e = this.getObjects();
		int hashCode = size();

		while ( e.hasMoreElements() ) {
			Object o = getNext(e);
			hashCode *= 17;

			hashCode ^= o.hashCode();
		}

		return hashCode;
	}


	boolean asn1Equals( ASN1Primitive o ) {
		if ( !(o instanceof ASN1Sequence) ) {
			return false;
		}

		ASN1Sequence other = (ASN1Sequence) o;

		if ( this.size() != other.size() ) {
			return false;
		}

		Enumeration s1 = this.getObjects();
		Enumeration s2 = other.getObjects();

		while ( s1.hasMoreElements() ) {
			ASN1Encodable obj1 = getNext(s1);
			ASN1Encodable obj2 = getNext(s2);

			ASN1Primitive o1 = obj1.toASN1Primitive();
			ASN1Primitive o2 = obj2.toASN1Primitive();

			if ( o1 == o2 || o1.equals(o2) ) {
				continue;
			}

			return false;
		}

		return true;
	}


	private ASN1Encodable getNext( Enumeration e ) {
		ASN1Encodable encObj = (ASN1Encodable) e.nextElement();

		return encObj;
	}


	ASN1Primitive toDERObject() {
		ASN1Sequence derSeq = new DERSequence();

		derSeq.seq = this.seq;

		return derSeq;
	}


	ASN1Primitive toDLObject() {
		ASN1Sequence dlSeq = new DLSequence();

		dlSeq.seq = this.seq;

		return dlSeq;
	}


	boolean isConstructed() {
		return true;
	}


	abstract void encode( ASN1OutputStream out ) throws IOException;


	public String toString() {
		return seq.toString();
	}
}
